In helicopter sling loading, sling leg length is partially controlled by adding or removing pre-designated lengths of chains. A coupling link is used to connect the additional chains. One example of a prior art chain coupling link is the Columbus McKinnon Hammerlok Model No. 664241. A major disadvantage of the aforesaid prior art coupling link is that a hammer and punch are needed to separate the coupling link sections. During testing, it is common to repeatedly change the chains from one test item to the next or even while on a single item. This is usually done outdoors with no work bench nearby. The test requires two people to perform the change. One person holds the coupling link steady while the other person lines up the punch with the hinge pin. The second person then drives the punch through with the hammer. This also requires clearance below the coupling link to permit hinge pin movement. Often, the first person is trying to hold the link off the ground. Other situations have occurred where the sling sets have been taken to the load already positioned for flight only to find that the additional chains have not been connected. This requires a return trip to the work shop to retrieve the hammer and punch thereby resulting in expenditure of even more time.
Other prior art chain coupling links are disclosed in U.S. Pat. Nos. 2,353,940, 3,132,395, 3,974,640, 4,063,413, 4,123,900, 4,134,256, 4,280,728, 4,418,526, 4,590,758, 5,732,545, 5,775,754, 5,851,040 and 7,269,937.
What is needed is an improved chain coupling link.